Lock



FIG. 1 is a top front perspective view of a lock showing my design;

FIG. 2 is a front view of FIG. 1;

FIG. 3 is a top view of FIG. 1; and,

FIG. 4 is a side view of FIG. 1.

All other surface(s) or portion(s) of my design not shown in the figures or otherwise described in the specification form no part of the claimed design. 

The ornamental design for a lock, as shown and described. 